U.S. Pat. No. 6,901,850, belonging to the same inventor as the present invention, discloses a machine with these features, in which there is described a prismatic block internally defining a chamber distributing the fluid to be injected and which is formed by a plurality of upright cylindrical through ducts, arranged equidistant and distributed according to several rows parallel to one another (see FIG. 4).
Patent application WO-83/02547 and patent EP-B1-1607001 likewise describe machines with the mentioned general features.
In all the cases the maintenance tasks for the injection chamber, particularly the assembly and disassembly thereof, to assure the leak-tightness of the unit, as well as the cleaning tasks are very expensive due to the difficulty and labor time involved.